Lebanese security forces have detained nine people, mostly Syrians, suspected of involvement in planning terrorist attacks, including a twin bombing last week, and smuggling extremists into the country.

Interior Minister Nohad Machnouk announced the arrests Sunday, three days after a twin suicide attack in a southern Beirut suburb killed 43 people and wounded more than 200.

"So far, the detained include seven Syrians and two Lebanese, one of them a [would-be] suicide bomber and the other a trafficker who smuggled them across the border from Syria," Machnouk said in a televised press conference.

He said the attackers were planning to strike the Rasoul al-Aazm hospital, which is run by the militant Hezbollah group, but changed their minds because of tight security.

Instead they targeted a busy street near the hospital during rush hour on Thursday evening. Machnouk says the attack was to involve five suicide bombers, but one was detained and two did not enter Lebanon.